The History of Philosophy

Erisistritus was a doctor who worked in the city of Alexandria on the coast of Egypt. He wants to explain why things move around inside the body by invoking mechanical processes that we could also see, for example, in machines. The thought here is not necessarily that void ever actually exists, or comes about, inside the body. But rather that in order to prevent a void from forming, things will move around in various ways. So it's almost like nature is a referee who will step in and shift things around at all costs to make sure no void can form. And that's why we never experience it.